The Improvement Research Of Determination Method Of Phthalic Acid Esters In Food

In this paper, oils and fat-containing food(the most difficult part in the determination of phthalate esters in food) were taken as matrixes. The national standard determination method of phthalate esters in food except the section of 5.2.1(process of oil-free sample) was analyzed and improved comprehensively, then a complete determination method for 17 kinds of phthalate esters in oils and fat-containing food was established. By study and validation, processing method for glassware used in the national standard was changed. Due to the merit of high-temperature resisting of glassware, it was placed directly in the muffle furnace and burned for 60 min at 500℃. This method is an alternative to the national standard, in which sample was immersed in acetone for 1 hour and then dried at 200℃ for 2 hours. Compared with the national standard, the improved method was simple, economic, environmentally friendly, low blank values and no cross contamination; Repeated oscillation extraction instead of vortices extraction was applied to the target extraction of oils and fat-containing food. This modified method can adapt to different detection work, reduce labor and improve the recovery rate; Instead of single gel permeation chromatography, matrix dispersion combined with gel permeation chromatography was applied to the purification of extracting solution. The method can achieve the result of both the purification effect and high recovery rate, reduce the pollution of the instruments, prolong device life, optimize the operating conditions, detail the specific operation method and make it more maneuverable. The qualitative and quantitative ions of Bis(2-methoxyethyl) phthalate, dihexyl phthalate, Bis(2-butoxyethyl)phthalate, dinonyl phthalate were reselected so that the qualitative was more scientific and the quantitative was more accurate. The detection range of the method was expanded,the method of the detection limit specified standard diisononyl phthalate has been based on. After the method was improved, the linear of each phthalate ester standard series was all above 0.999. The blank value of each phthalate acid esters test solution was below 0.1ug/mL. The recoveries of phthalate acid esters in oil and oily food were more than 90%. When the content of phthalate acid esters in oil and oily food was 2.5 mg/kg~3.5 mg/kg, the coefficient of variation(n = 6) of the results was below 10%. The accuracy and precision of the method was good. In summary, the method had advantages of economic, environmental, good purifying effect, strong operability, small instrument contamination, good linearity, high recovery, low blank value, high precision. The improved method was a powerful weapon to solve the detection of phthalate acid esters in complex matrixs.